What started as one Marine's idea to help his comrades do their jobs more efficiently has blossomed into a thriving Longmont-area business.

Former U.S. Marine Reconnaissance Sgt. Richard Fitzpatrick was retired from the Marines and working in software when he took an idea from his military days and turned it into a product.

The Magpul is a simple rubber device that fits around the outside of a magazine - the clip that holds ammunition for automatic and semiautomatic weapons - and lets the user pull the clip from his ammo pouch faster and easier than he could otherwise, allowing for faster reloading.

Marines and soldiers had traditionally used parachute cord for that purpose, Fitzpatrick said, but tying the cord around the magazines was tedious and time-consuming.

"If you wanted to do 25 magazines, that would take you an afternoon," he said.

With help from friends in the design field and the plastics industry, Fitzpatrick spent about three years perfecting the Magpul and started producing and selling it out of his basement.

Skepticism from Marines and soldiers quickly turned to a wide embrace of the product, and in 2004, five years after he launched his company - Magpul, named after its first product - Fitzpatrick started renting warehouse space to keep up with demand.

Today Magpul employs 25 people full-time at its headquarters and it makes a variety of gun accessories it sells to military, security and law enforcement personnel.

While the Magpul is still popular, all the company's other products are made from a special polymer - a super-hard plastic resistant to wear and tear and the elements.

One recent addition to the company's lineup is the PMAG - a magazine made of that polymer.

"It's been a huge seller," said Drake Clark, who handles marketing for Magpul. "We now have two teams to build PMAGs, and we're bringing on a third and fourth team."

Like the Magpul, the company developed the PMAG on its own, not at the request of the military. The skeptics were many. A magazine made completely from plastic would never work, the critics said.

To prove the PMAG was for real, Clark had someone film him driving over the top of several different magazines, including the PMAG, in his pickup truck. In the end the PMAG was the only magazine that wasn't destroyed.

The video was posted to YouTube and the orders started coming.

"The guerrilla marketing that we do is a huge part of my job," Clark said.

Clark is the star of another YouTube video called "fully automatic flashlight," which features him showing a combination flashlight/machine gun the company invented. It's not a product the company actually sells, but it came up with the idea to draw attention to what Magpul does make, Clark said. The video has succeeded in its mission, with millions of views since being posted.

"We are incredibly hot in our industry right now," he said. "Things like that folding flashlight - that's really getting people to take a look."

Magpul sells its products two different ways: through a network of dealers and distributors and directly to soldiers and others through its Web site.

"It could be anybody from Joe shooter in Idaho to G.I. Joe in Iraq," Clark said of Magpul's customers.

Foreign militaries are part of the customer base, he said, adding, "We are extremely, extremely strict about who we sell to."

Magpul's business has doubled every year since 1999, Fitzpatrick said. The success has allowed the company to put more money into research and development, and that brainstorming has generated the company's latest venture.

Magpul has gone beyond making gun accessories.

Fitzpatrick said he and others in the company thought the next generation of rifles being produced for the military were subpar - sometimes at the cost of tens of millions of dollars to the U.S. taxpayer.

What started as a contract for building a stock for a submachine gun led Magpul's team to believe they could design their own gun.

"We sat around about 12 hours straight going through what this gun would and wouldn't have," Fitzpatrick remembers. "We were going to make a statement. A small bunch of yahoos in Colorado: 'We can do this. We're going to build this thing for under $100,000.'"

The team took what it thought were the best attributes of the AR-15 and the M-16 rifles and added their own twists. The result was the Magpul Masada, which debuted at the 2007 Shot Show in Orlando, Fla. The industry trade show is billed as the world's largest showcase of firearms.

"The response was just crazy," Fitzpatrick said. "What happened at the show was we were surrounded. Our booth was mobbed."

Magpul has since licensed the Masada to Bushmaster, one of the world's largest makers of military arms. Bushmaster has changed the name of the gun - it's now the ACR, or Adaptive Combat Rifle - and full-scale production has begun, with Magpul getting royalties off each sale.

Meanwhile, the company continues to do brisk business in PMAGs, stocks, and other accessories. Tens of thousands of the replacement stocks the company makes for the M-16, for example, are being used in Iraq and Afghanistan, Clark said.

Ex-Air Force himself, Clark said the company takes plenty of pride in its work. All four branches of the U.S. military and the Coast Guard are represented among its 25 employees, he said, adding, "Everything that we make and we sell is made in the United States."